1. The findings presented in this manuscript played a big role in Harold Varmus and Michael Bishop winning the Nobel prize in Medicine and Physiology, 1989. Why do you think this is the case? 2. Much...

1. The findings presented in this manuscript played a big role in Harold Varmus and Michael Bishop winning the Nobel prize in Medicine and Physiology, 1989. Why do you think this is the case?

2. Much of the data in this paper was produced by analyzing homology between two DNA samples. Describe two methods that were used in this paper to assay DNA-DNA homology.

3. What is B77 ASV and why was it used in these studies?

4. What is a Cotcurve and what does the Cot ½value tell us about the re-annealing of denatured DNA?

5. What is the purpose of the radiolabeled B77 DNA annealed to chicken DNA added to all samples studied in Fig. 2?

Stehelin, D., H. Varmus, J. Bishop, and P. Vogt. DNA related to the transforming gene(s) of avian sarcoma virus is present in normal avian DNA. Nature 260:170-173, 1976. Define the following terms: Neoplastic transformation Homologous Fibroblast Oncogenesis ASV and RAV-O cDNA Molecular hybridization Cistron Denature Anneal Reassociation Duplex formation Paragraphs 1. As background to your paper, summarize the authors’ comments in the first 14 lines. What is the purpose of their experiment? 2. What is the experimental procedure used to make cDNA sequences complementary to parts of the viral genome? The authors used ASV deletion mutants with missing DNA sequences. What is important about these particular DNA segments? What is the difference between ASV and RAV-O? 3. What is the experimental procedure used to compare the DNAs of ASV and genomes of the various bird species? What did they find when they made the comparisons? What does the result say about ASV in relation to bird evolution? 8. Describe the similarities among various birds of the cDNAsarc sequence. Don’t worry about the details, but do describe the authors’ conclusions at the end of paragraph 6 and the middle of paragraph 8. 9. They note that genetic information required for cancer is part of the DNA sequence of ASV, and that it is present in the DNA of several bird species. What does that result say about the mechanism of cancer in ASV-infected birds? 10. ignore 11. ignore 12. The authors think that the avian DNA homologous to cDNAsarc serves some function that accounts for its conservation throughout bird evolution. That DNA may represent a gene needed for some important cellular function. They did not at the time know what it was; you need to find out and make it part of your paper.